Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Genus Description - Monoecious or polygamous; staminate fls in small clusters near the base of the twigs of the season; fertile fls solitary or sometimes paired, from the upper axils of the same twigs, often lacking stamens; cal deeply 5-parted; anthers introrse; style very short, with elongate, recurved-divergent stigmas; fr a drupe with thin, ± sweet pulp and a hard stone; embryo curved; woody pls with entire or serrate lvs 3-nerved from a ± oblique base; fls ephemeral, borne in early spring. 70, mainly N. Hemisphere.